Etching Process

Abstract

Mixtures of fluorine and inert gases like nitrogen and/or argon can be used for etching of semiconductors, solar panels and flat panels (TFTs and LCDs), and for cleaning of semiconductor surfaces and plasma chambers. Preferably, fluorine is comprised in an amount of 15 to 25 vol.-% in binary mixtures. The gas mixtures can be used as substitute or drop-in for respective mixtures comprising NF 3 and permit a very flexible operation of plasma apparatus. For example, apparatus tuned for NF 3 /Ar mixtures can be operated without further tuning using fluorine and argon, optionally together with nitrogen. The fluorine content is preferably in the range of 1 to 5 vol.-%, if ternary mixtures of fluorine, nitrogen and argon are used.

1 . A process for etching or cleaning the surface of semiconductor material, solar panels or flat panels (TFTs and LCDs), or cleaning chambers of apparatus used for semiconductor manufacturing, wherein a mixture comprising or consisting of fluorine and one or more inert gases selected from the group consisting of nitrogen and noble gases is used. 
   
   
       2 . The process according to  claim 1 , wherein the process is a chamber cleaning process. 
   
   
       3 . The process according to  claim 1 , wherein a binary mixture is used, and fluorine is comprised in the binary mixture in a range between 1 and 35 vol.-%. 
   
   
       4 . The process according to  claim 3 , wherein the binary mixture consists of fluorine and nitrogen, or fluorine and argon. 
   
   
       5 . The process according to  claim 1 , wherein a ternary mixture is used, said ternary mixture comprising fluorine, nitrogen and a noble gas. 
   
   
       6 . The process according to  claim 5 , wherein the ternary mixture consists of fluorine, nitrogen and argon. 
   
   
       7 . The process according to  claim 6 , wherein the fluorine content lies in the range of 1 to 5 vol.-%, the volume ratio between fluorine and nitrogen lies in the range of 15:85 to 25:75 argon being the balance to 100 vol.-%. 
   
   
       8 . The process according to  claim 1 , wherein the pressure is in the range between 100 and 2000 Pa. 
   
   
       9 . The process according to  claim 1 , wherein the process is plasma-supported and the temperature lies in the range between 100 and 350° C. 
   
   
       10 . The process according to  claim 1 , wherein the process is performed plasma-free and that the temperature is at least 400° C. 
   
   
       11 . The process according to  claim 1 , wherein an inorganic material is etched, or wherein chambers are cleaned which are contaminated by an inorganic material. 
   
   
       12 . The process according to  claim 11 , wherein the inorganic material is amorphous Si, SiO x N y , SiO 2 , TaN, TiN or W. 
   
   
       13 . The process according to  claim 11 , wherein the inorganic material is W, and wherein the gas mixture comprises or consists of fluorine and nitrogen. 
   
   
       14 . The process according to  claim 12 , wherein the inorganic material is amorphous Si, SiO x N y , SiO 2 , TaN or TiN, and wherein the gas mixture comprises or consists of fluorine and nitrogen. 
   
   
       15 . The process according to  claim 12 , wherein the inorganic material is amorphous Si, SiO x N y , SiO 2 , TaN or TiN, and wherein the gas mixture comprises or consists of fluorine and argon. 
   
   
       16 . The process according to  claim 1 , wherein an organic material is removed from the surface of semiconductors, solar panels or flat panels (TFTs and LCDs), or wherein chambers contaminated with an organic material are cleaned. 
   
   
       17 . The process according to  claim 16 , wherein the organic material is a fluorinated polymer originating from etching semiconductors, solar panels or flat panels (TFTs and LCDs) with fluorinated carbon compounds, optionally in the presence of hydrogen, as etching gas. 
   
   
       18 . The process according to  claim 16 , wherein oxygen is additionally present during removal of said organic material. 
   
   
       19 . The process according to  claim 1 , wherein mixtures comprising or consisting of fluorine and one or more inert gases are used as drop-in substitute for gas mixtures comprising NF 3  and one or more inert gases. 
   
   
       20 . The process according to  claim 19 , wherein gas mixtures comprising or consisting of fluorine and one or more inert gases are used as drop-in substitutes for NF 3  and inert gases in CVD, PVD or ALD plasma apparatus. 
   
   
       21 . The process according to  claim 19 , wherein the inert gas of the fluorine/inert gas mixture corresponds to the inert gas of the NF 3 /inert gas mixture. 
   
   
       22 . The process according to  claim 20 , wherein the inert gas of the fluorine/inert gas mixture does not correspond to the inert gas of the NF 3 /inert gas mixture, and wherein the inert gas of the NF 3 /inert gas mixture is additionally introduced into the plasma apparatus. 
   
   
       23 . The process according to  claim 22 , wherein a fluorine/argon gas mixture is used as drop-in substitute for an NF 3 /argon gas mixture. 
   
   
       24 . The process according to  claim 22 , wherein a fluorine/nitrogen gas mixture is used together with argon as a drop-in substitute for an NF3/argon gas mixture. 
   
   
       25 . The process according to  claim 20 , wherein the substitution is performed without tuning the apparatus to the fluorine containing gas mixture. 
   
   
       26 . A plasma apparatus for etching semiconductors, solar panels and flat panels (TFTs and LCDs), tuned for use of NF3 as etching gas component, having a content of a mixture comprising or consisting of fluorine and one or more inert gases selected from the group consisting of nitrogen and the noble gases. 
   
   
       27 . The plasma apparatus according to  claim 26 , comprising a container, connected to it, with a mixture comprising or consisting of fluorine and one or more inert gases selected from the group consisting of nitrogen and the noble gases. 
   
   
       28 . The plasma apparatus according to  claim 26 , comprising a mixture consisting of fluorine and argon, fluorine and nitrogen, or fluorine, argon and nitrogen. 
   
   
       29 . The plasma apparatus according to  claim 26 , wherein said plasma apparatus is tuned for NF 3 /argon mixtures. 
   
   
       30 . A method of using fluorine in a plasma apparatus wherein said fluorine is used as component of gas mixtures as drop-in substitute for NF 3  in said plasma apparatus. 
   
   
       31 . The method according to  claim 30  for etching or surface cleaning of semiconductors, solar panels, and/or flat panels, or for chamber cleaning. 
   
   
       32 . The method according to  claim 30  wherein said plasma apparatus is tuned to NF 3  comprising gases. 
   
   
       33 . The method according to  claim 30 , wherein the gas mixture further comprises one or more inert gas selected from the group consisting of nitrogen and the noble gases. 
   
   
       34 . The method according to  claim 33 , wherein the gas mixture consists of fluorine and nitrogen, fluorine and argon, or fluorine, nitrogen and argon. 
   
   
       35 . A gas mixture consisting of fluorine and one or more inert gases selected from the group consisting of nitrogen and the noble gases. 
   
   
       36 . The gas mixture according to  claim 35 , consisting of fluorine and nitrogen in a volume ratio of 1:99 to 35:65, fluorine and argon in a volume ratio of 1:99 to 35:65. 
   
   
       37 . The gas mixture according to  claim 36  wherein the volume ratio is 18:82 to 22:78 for the gas mixture consisting of fluorine and nitrogen, or consisting of fluorine and arson. 
   
   
       38 . The gas mixture according to  claim 35 , consisting of fluorine, nitrogen and one of the noble gases. 
   
   
       39 . The gas mixture according to  claim 38 , consisting of fluorine, nitrogen and argon. 
   
   
       40 . The gas mixture according to  claim 38 , wherein the fluorine content is in the range of 1 to 5 vol.-% and the volume ratio of fluorine to nitrogen is in the range of 15:85 to 25:75, the noble gas being the balance to 100 vol.-%.